Die-casting machine with bell crank drive



Dec. 20, 1966 w. BATTENFELD ETAL 3,292,214

DIE-CASTING MACHINE WITH BELL CRANK DRIVE Filed March 17, 1964 5Sheets-Sheet l /NVENTOFS 1% M w w WM Wm X f r Deb. 20, 1966 W.BATTENFELDETAL 3,292,214

DIE-CASTING MACHINE WITH BELL CRANK DRIVE Filed March 17, 1964 i5Sheets-Sheet 2 Dec. 20, 1966 w. BATTENFELD ETAL 3,

DIE-CASTING momma WITH BELL CRANK DRIVE 5 Sheets-Sheet 5 Filed March 17,1964 WVEwv/Ps m M Dec. 20, 1966 w. BATTE NFELD ETAL 3,292,214

DIE-CASTING MACHINE WITH BELL CRANK DRIVE Filed March 17, 1964 5Sheets-Sheet 4 1966 w. BATTENFELD ETAL 3,

DIE-CASTING MACHINE WITH BELL CRANK DRIVE Filed March 17, 1964 sSheets-Sheet s United States Patent 3,292,214 DIE-CASTING MACHINE WITHBELL CRANK DRIVE Werner Battem eld and Siegfried Schindler,Meinerzhagen, Germany, assignors to Firma Gebruder Battenfeld,Meinerzhagen, Germany, a corporation of Germany Filed Mar. 17, 1964,Ser. No. 352,519 Claims priority, application Germany, Mar. 25, 1963, B71,280 2 Claims. (Cl. 1830) The present invention relates to adie-casting machine with a bell crank drive for the working ofthermo-plastic artificial material, whereby, for the closing and openingmovement of the mold, as well as for the working stroke and returnstroke of the die-casting piston, a single drive only is provided, thedriving connecting rod of which is pivotally connected with pairs ofbell-cranks of diiferent lengths, of which the longer pair ofbell-cranks engages a cross-traverse, which connects two longitudinallongerons carrying the mold carrying plate for a rigid locking of themold, while the shorter pair of bell-cranks is pivotally connected witha piston carrier plate. A pressure pillow built into the piston carrierplate retards the movement of the die-casting piston, so that thedie-casting mold is rigidly locked, before the movement of thediecasting piston is terminated.

The present invention differs in an advantageous manner substantiallyfrom a bell-crank drive casting machine in accordance with the generalnotion for working of thermoplastic artificial material by the fact,that, on the one hand, all three bearings of the pairs of cranks aredisposed movably relative to the drive and that, on the other hand, atthe start of the mold closing movement, the driving connecting .rod andthe longer pair of bellcranks, engaging a longeron cross-traverse, aredisposed generally in the same direction and the driving connect ing rodexerts at first pressure upon the longer pair 01 bell-cranks, while atthe start of the opening movement of the mold the driving connecting rodis disposed nearly in the same direction with the shorter pair ofbell-cranks, engaging the piston carrying plate, and exerts at first apulling effect upon the shorter pair of bell-cranks.

It is, therefore, one object of the present invention to provide adie-casting machine with a bell crank drive, wherein the die-castingmold is at first completely closed, before the actual casting processstarts and is mechanically locked before the casting process isterminated, and in particular, in such manner, that at first the longerpair of bell-cranks, causing the closing of the die-casting mold parts,is operated slidingly by the driving connecting rod, and only after theclosing of the die-casting mold the working stroke of the piston carrierstarts. Since the force of the pressure pillow built into the pistoncarrier is adjusted to be smaller than the force with which the pistoncarrier is moved, a retarded movement speed of the die-cast piston iscaused relative to the piston carrier, due to the resistance of thedie-cast mass in the plastification cylinder, so that the die-castprocess is terminated due to the release of the tension of the pressurepillow after the locking of the die-cast mold and a standstill of thedriving system and the required after-pressure is maintained. Inaddition, during the opening process, the pair of bell-cranks engagingthe piston plate is at first operated in a pulling manner during theopening process, so that the piston returns before the mold opens.

For the practical realization of the present invention, a crank drive isused, the driving connecting rod of which engages the center joint ofthe pairs of bell-cranks and, thereby, the center axis of the drivecrank is disposed on the side of the die-cast mold in a plane slightlyin front of the center joint of the double-armed levers.

By such arrangement, it is brought about that the crank pin connectingthe connecting rod with the drive disc is disposed at the start of theclosing movement on the side of the driving disc opposite the shorterpair of bell-cranks, so that the connecting rod is disposedsubstantially in the same direction with the longer pair of bell-cranks,whereby it is achieved, that this pair of double-armed levers is atfirst displaced and thus also the mold is at first closed, prior to thestart of the diecasting process by means of the die-cast piston. On theother hand, the crank pin, caused by the rotationof the driving disc, isdisposed at the start of the opening movement on the side of the drivingdisc opposite the longer pair of bell-cranks, so that the connecting rodand the shorter pair of bell-cranks are disposed about in the samedirection, whereby it is brought about that at first, it operates in apulling manner, thus withdrawing at first the die-cast piston, beforethe mold opens.

With these and other objects in view, which will become apparent in thefollowing detailed description, the present invention will be clearlyunderstood in connection with the accompanying drawings, in which:

FIGURE 1 is an axial section of the die-casting machine designed inaccordance with the present invention, and in particular, shown at thestart of the closing movement;

FIG. 2 is an axial section similar to that shown in FIG. 1, showing themold in a closed position and also after the completed die-castingprocess;

FIG. 3 is a top plan view of the die-casting machine, showing the moldin its closed position and indicating the position after completion ofthe die-casting process;

FIG. 4 is a fragmentary section of the machine within the range of thedie-casting piston, likewise in the spraying position; and

FIG. 5 is a fragmentary section similar to that shown in FIG. 4,indicating the completely open position.

Referring now to the drawings, the die-casting machine designed inaccordance with the present invention comprises a frame 10 havingmounted therein a crankdrive, a driving disc 12 of which is mounted in ahearing 11 and is driven by a worm gear 13. A driving connecting rod 14,which is connected with the driving disc 12 by means of a crank pin 15,engages pivotally a center joint 16 of two pairs of bell-cranks 19 and20, of which the pair of bell-cranks 19 is longer than the pair ofbellcranks 20. The pair of bell-cranks 19 in turn is con nected with across traverse 21 by means of the pivot 17, which cross traverse 21connects rigidly two longitudinal longerons 22. These longitudinallongerons 22 are slidingly guided in bearings 23 and support a moldcarrying plate 25 at their ends disposed remote from the cross traverse21.

During the rotating movement of the driving disc 12 in clockwisedirection, the cross-transverse 21 is displaced in the direction of thearrow, shown in FIG. 1, whereby the mold carrying plate 25 with a mold26 is moved towards the spray side of a tool carrying plate 27 and themold is closed. A nozzle 28 seals itself thereby against the heatcylinder side of the spraying mold. The closing movement is limited bythe abutment of the nozzle plate 27 on a heating cyinder 29. Since nowthe 'crank pin 15 did not reach yet the highest position, a pistoncarrier pate 30, into which a hydraulic pneumatic pressure pillow isbuilt in, moves in the direction of the arrow B (FIG. 2). A sprayingpiston 31 presses the spraying material received in front thereofthrough a plastification cylinder 32 into the mold 26.

Since now during this total performance, the moving speed of the drivein the direction of the arrow B is greater than that of the movement ofthe piston 31, a piston 31a of the pressure pillow is not operative.Upon termination of the drive movement, the links 18, 16 and 17 of thepair of bell-cranks 19 and 20 are in the position shown in FIG. 2 of thedrawings, so that the mold is mechanically locked. 'I he piston carrierplate 30 comes then to a standstill at an abutment 33 of the heatingcylinder plate, so that the mentioned rigid locking comes about.

It now the mechanical locking is obtained, the piston 31 terminates, dueto the efiect of the pressure pillow or also by the force of a spring,the filling of the mold. Upon correct dosage, by means of a dosingdevice 34, a material surplus will be present in the plastificationcylinder 32, so that the pressure pillow does not engage the abutment onthe piston side and, thereby, maintains the required pressure for thespraying process.

After the filling of the mold, the crank pin of the driving disc 12moves again downwardly from its highest position, however, now on theopposite side of the disc 12, so that the connecting rod 14 is disposedin about the same direction with the shorter pair of bell-cranks 20, andat first, effects the latter in a pulling manner during the openingmovement and by withdrawing the piston carrier plate 30, while duringthe closing movement opposite conditions prevail, so that then first thelonger pair of bell-cranks 19 is operated.

It is to be understood that the shown and described embodimentconstitutes merely an example for the realization of the presentinvention, without being limited thereto, rather within the scope of thepresent invention, other embodiments and applications are possible. Thisrelates in particular to the construction of the drive, which can bedesigned also as a hydraulic drive, since it is only essential that thedriving connecting rod can be effective in two directions.

We claim:

1. A die-casting machine for the working of thermoplastic artificialmaterial comprising a frame,

a crank-drive including a connecting rod mounted in said frame,

two pairs of bell-cranks of different lengths pivotally connected at acenter pivot with the free end of said Connecting .rod,

said crank drive constituting the sole drive for the closing and openingmovement of a mold as well as for the working stroke and the returnstroke of a feeding? piston, a cross-traverse pivotally connected withthe longer one of said pairs of bell-cranks,

two longerons connected by said cross-traverse and carrying a moldcarrying plate,

a piston carrier plate having a piston reciprocating therein and pivotedto the shorter of said pairs of bell-cranks,

a pressure pillow built into said piston carrier plate and retarding theaxial movement of said piston, so that the die-casting mold is rigidlylocked, prior toithe termination of the movement of said piston,

all three bearings of said pairs of bell-cranks are movably disposedrelative to said drive, and

at the start of the mold-closing movement the driving connecting rod andthe longer of said pairs of bellcranks being disposed substantially inthe same direction and exerting a pushing pressure upon the longer ofsaid pairs of bell-cranks, while at the start of the mold openingmovement said driving connecting rod and the shorter of said pairs ofbell-cranks being disposed substantially in the same direction and ex-.

erting a drawing effect upon the shorter of said pairs of bell-cranks.

2. The die-casting machine, as set forth in claim 1,2

References Cited by the Examiner,

UNITED STATES PATENTS FOREIGN PATENTS 5/1957 France. 1/ 1929 Germany.

J. SPENCER OVERHOLSER, Primary Examiner.

W. L. MCBAY, Assistant Examiner.

1/1964 Rees 18-3Q

1. A DIE-CASTING MACHINE FOR THE WORKING OF THERMOPLASTIC ARTIFICIALMATERIAL COMPRISING A FRAME, A CRANK-DRIVE INCLUDING A CONNECTING RODMOUNTED IN SAID FRAME, TWO PAIRS OF BELL-CRANKS OF DIFFERENT LENGTHSPIVOTALLY CONNECTED AT A CENTER PIVOT WITH THE FREE END OF SAIDCONNECTING ROD, SAID CRANK DRIVE CONSTITUTING THE SOLE DRIVE FOR THECLOSING AND OPENING MOVEMENT OF A MOLD AS WELL AS FOR THE WORKING STROKEAND THE RETURN STROKE OF A FEEDINGPISTON, A CROSS-TRAVERSE PIVOTALLYCONNECTED WITH THE LONGER ONE OF SAID PAIRS OF BELL-CRANKS, TWOLONGEROUS CONNECTED BY SAID CROSS-TRAVERSE AND CARRYING A MOLD CARRYINGPLATE, A PISTON CARRIER PLATE HAVING A PISTON RECIPROCATING THEREIN ANDPIVOTED TO THE SHORTER OF SAID PAIRS OF BELL-CRANKS, A PRESSURE PILLOWBUILT INTO SAID PISTON CARRIER PLATE AND RETARDING THE AXIAL MOVEMENT OFSAID PISTON, SO THAT THE DIE-CASTING MOLD IS RIGIDLY LOCKED, PRIOR TOTHE TERMINATION OF THE MOVEMENT OF SAID PISTON, ALL THREE BEARINGS OFSAID PAIRS OF BELL-CRANKS ARE MOVABLY DISPOSED RELATIVE TO SAID DRIVE,AND AT THE START OF THE MOLD-CLOSING MOVEMENT THE DRIVING CONNECTING RODAND THE LONGER OF SAID PAIRS OF BELLCRANKS BEING DISPOSED SUBSTANTIALLYIN THE SAE DIRECTION AND EXERTING A PUSHING PRESSURE UPON THE LARGER OFSAID PAIRS OF BELL-CRANKS, WHILE AT THE START OF THHE MOLD OPENINGMOVEMENT SAID DRIVING CONNECTING ROD AND THE SHORTER OF SAID PAIRS OFBELL-CRANKS BEING DISPOSED SUBSTANTIALLY IN THE SAME DIRECTION ANDEXERTING A DRAWING EFFECT UPON THE SHORTER OF SAID PAIRS OF BELL-CRANKS.